Most likely air in the system. Bleeding the brakes is a doodle though, dot4 brake fluid is around £2.50 from Eurocarpart for 500ml and you can pick up a 'one man' bleed kit from halfords for around a fiver. Still a lot easier with two people though,
Thanks Matt. It lools like I'll have to do this. The car was only mot'd yesterday (after the calipers were fitted) so it must have performed alright on the brake rollers :s